I know someone that had a link in his AIM profile to a webpage on a server that he owned which contained his "real" profile. Ever seen those Sub-Profile links in peoples info? Know how it records the screen name of the person who clicked the link? He had some kind of script that did the same thing, and recorded the IP address as well and wrote the info to a file along with a date/time stamp. So he could open up the file and see the last time x person viewed his profile and what their IP was at the time. If he wanted it for whatever reason, he'd just IM them and tell them there were some new pics or something on his profile...
Food for thought.
Dont know exactly how he did it, if I talk to him soon and remember I'll ask him.